Automatic means for shaking suction cleaner filters



July 8, 1958 K. J. WAHLBORG 2,842,225

AUTOMATIC MEANS FOR SHAKING SUCTION CLEANER FILTERS Original Filed Dec. 15, 1955 s Sheets-Sheet 1 aw/1M.

% ATITOIRNEIY A TOMATIC MEANS FOR SHAKING SUCTION CLEANER FILTERS 5 Sheets-Sheet 2 Original FiIed Dec. 15, 1953 1 a v M w. 5 a I g l 3 0 0. mi N a 0 a i w m 2 4 6 7 6 21 3 4 I 4 lufiMFhfifi M.

a a m BYQWV/Z/ h 11 TTORNE 1 July 8, 1958 K. J. WAHLBORG AUTOMATIC MEANS FQ'R SHAKING SUCTION CLEANER FILTERS Original Filed Dec. 15, 1953-" 3 Sheets-Sheet 3 m lllllI/lllllffllf/I/I m I n I I h ATTORNEY 7 6 6I I r g A #0 0 I Wv. Mm aw W 6 m m 3 1 ml 1 a N w United States Pate-n ;v

AUTOMATIC MEANSFORSHAKING SUCTION CLEANER FILTERS Karl John Wahlborg, Bromma, Sweden, assignor to Alrticbolaget Elektrolux stockholm,Sweden, a corporation of'Sweden Continuation of application SerialNo. 398,325, December 15,1953. This application March 5, 1957, Seriai No. 644,095

'Claimspriority, application Sweden December 20, 1952 17 Claims. (Cl. 183-37) My invention relates tosuction cleaners of the type that. employ a dust separating member which tends to become. clogged with dust and dirt separated from air.

This application is a continuation of my application Serial No. 398,395, filed December 15, 1953, now

abandoned.

it is an object of my invention to providean improvement for automatically suspending the normal operation of such-a suctioncleaner and imparting movement to the dust separating member to dislodge dust and dirt therefrom.

Another object is to provide such an improvement for automatically resuming normal operation of the cleaner.

after dislodging dust and dirt from the dust separating member.

A further object is to provide such an improvement for automatically impartingv movement to the dustseparating men'iberrespons'ive to an operating condition which reduces the efiiciency of the cleaner.

A still further object is to provide such an improvement for automatically imparting movement to the dust separating member responsive to such an operating con-' quently terminate the operation of such mechanism.

The above and other objects and advantages of my.

invention; will'become apparent as the following description proceeds, and the features'of'novelty which characerize the invention will be pointed out with particularity in the claims annexed to 'and*forming a part of this specification.

For a better'understandingof my invention, reference may be, had" to the following description taken in connection with the accompanying'drawings in which:

' Fig. 1 is ayertical sectional view of a suction cleaner embodyingwmy invention;

Fig. 2 is a fr'agmentaryvertical'sectional view of the top, part of the suction cleaner' shown in Fig. 1 to illustrate details'more clearly'f Fig. 3 is a horizontal view, partly'broken' away and in section, taken at line '3-,3'of Fig. 1;

Figs. '4 and are vertical sectional views taken at lines 4,4and ,5'5,'.respectively, of 'Fig. 1'; and

Fig. dis a fragmentary sectional view of parts of a v suction cleaner like-that showndn Figs. lto 5 illustrating another embodiment of the' invention.

Referring-to Fig; l, thesuction-cleaner which I'- have 2,842,225 Patented July 8, 1958 member 10 includes spaced apart horizontal walls or plates 141a and 105, respectively, the bottom plate 1% having an opening to receive the top open end of a vertically disposed dust receptacle 14-. The receptacle 14 is urged upwardly against a resilient gasket 15 in sealing relation therewith by a clamp or holding member 16 which acts resiliently against the bottom of the receptacle 14 and is fixed to the bottom frame member 11.

The resilient gasket 15, which is of annular form, constitutes the outer peripheral edge portion of a filter element or dust separating member 17 having a central opening which receives the lower end of an L-shaped conduit 18 having an inlet 19, such inlet end of the conduit being positioned in an opening formed in a side wall of a top cover 20 which serves as a protective hood for the cleaner. The dust separating member 17 is formed with circular folds 21 which are concentric with respect to one another, the points of the folds passing over top and bottom wires 22 and 23, respectively. The bottom wire 23 is held in place by elements 24 which are fixed to the-top horizontal wall 10a, and the top wires 22 are fixed to and carried by a. movable bridge member 25 which will be described more fully hereinafter. The innermost told 21 is tightly secured at 26 to the lower end of the conduit 18.

To facilitate removal of dust and dirt which collects in the receptacle 14, the latter is lined with a bag 27 which may be of the throw-away type and formed of paper or other suitable material impermeable to dust. 'A

bafile 28 is provided in the upper part of the receptacle 14 to control the movement of air and minimize movement of dust which which has collected in the receptacle, especially by eddy currents which tend to lift dust from the bottom of the receptacle. To prevent such eddying of dust particles, the central part of the baffle 28 is formed with an upwardly extending conical-shaped portion 29 which is enveloped by circular section having an upwardly sloping wall, such wall having a number of spaced apart openings 30. The extreme upper part of the receptacle 14 is slightly enlarged to receive the top folded edge of the baffle 28 which in turn receives the top edge of the bag 27, the arrangement being such that,

when the receptacle 14 is maintained in position by the holding member 16, the bafiie will also be maintained in position with the top folded edge thereof bearing against the resilient gasket 15.

The bottom horizontal plate 10b is also provided with an opening to receive a top closure member 31 for the is discharged from the motor fan unit 33 at the outlet 34 located closely adjacent to the bottom member 11.

A suction hose (not shown) is adapted to be removably secured to the inlet 19 of the suction cleaner in any suitable rnanner. Suitable cleaning appliances may be connected to a wand which in turn is connected to. the outer free end of the suction hose and through which air is drawn through conduit 18 by the motor fan unit 33. To facilitate movement of the suction cleaner when thelatter is being operated, the bottom member 11 is provided with suitable wheels 35 and 36. v

During operation of the suction cleaner, dust-laden air is drawn through the conduit 18 into the space 37 below the dust separating member 17 and above the baflle 28. The baffle 28 promotes reversal of the direction of air movement in space 37, and such air flows upwardly toward the dust separating member or filter element 17 which separates dust and dirt from the air. Air free of such dust and dirt passes through the dust separating member 17 and flows through a chamber 38 formed by the spaced apart plates a and 10b and the collar or opening 32 in the closure plate 31, such air being discharged by the motor fan unit 33 at the outlet 34.

Since dust and dirt are trapped at the bottom face or surface of the dust separating member 17, there is a tendency for the latter to become clogged during operation of the cleaner. Suitable mechanism is provided to shake and clean the dust separating member, such shaking movement imparted to the folds 21 of the dust separating member being effective to dislodge dust and dirt from the underside thereof. As best shown in Fig. 4, the dust separating member shaking mechanism includes an inverted U-shaped stirrup 39 having a top closed end 40 and side arms 41 depending downward therefrom which are arranged to act and bear against the bridge member 25. If desired, the lower end of one of the side arms 41 may be anchored at 42 to the bridge member in any suitable manner, as indicated in Fig. 4.

The bridge member 25, which is vertically movable, is resiliently biased upwardly by a pair of springs 43, each of which is disposed about a vertical pin 44 having its lower end anchored to an angle member 45 and its upper end extending through an opening in the bridge member. When downward movement is imparted to the stirrup 39, the vertical arms 41 thereof will move the bridge member 25 downward and compress the springs 43, as best seen in Fig. 4. When the bridge member 25 is moved downward in this manner, slack is provided in the folds 21 of the dust separating member or filter 17,. as best seen in Fig. 2. When downward movement isno longer imparted to the stirrup 39 and the latter is free to move upwardly, the springs 43 which are under considerable tension, are capable of imparting a quick and sudden upward movement or thrust to the filter 17, such movement of the filter snapping the individual folds 21 to dislodge dust and dirt from the underside thereof which collects in the dust bag 27 within the receptacle 14.

In accordance with my invention, shaking movement is imparted to the dust separating member 17 responsive to an operating condition which occurs when the dust separating member becomes clogged with dirt and the efficiency of the suction cleaner is reduced. In the preferred embodiment of the invention being described, fluid operated mechanism is provided to impart movement to the stirrup 39 and subsequently release the latter responsive to a predetermined pressure differential at opposite sides of the dust separating member 17 due to dust and dirt trapped at the underside thereof. Such fluid operated mechanism includes two housings 46 and 47 which are disposed underneath the protective hood 20 and carried by the top plate 10a, as seen in Figs. 1, 4 and 5.

The housing 46 is divided by a vertically disposed partition having a movable portion or diaphragm 48 into spaces 49 and 50, the space 49 being connected by tubing 51 to the inlet end of the conduit 18, so that the space 49 will be essentially at the same pressure as the pressure at the inlet 19 and at the underside of the dust separating member 17. As shown in Fig. 1, the space of housing 46 is provided with a horizontally disposed movable part or diaphragm 52 to which is fixed a valve member 53 adapted to move toward and from the rim or collar 32 which serves as a seat for such valve member. The valve member 53 is provided with a stem 54 which is vertically movable in a hollow sleeve 55 carried in the upper part of the housing 46. The valve stem 54, which is notched at 56 at a region below the extreme upper end thereof, is normally held in the raised position shown in Fig. 1 by a horizontal rod 57 fixed to and movable with the diaphragm 48. The rod 57, which is formed with an intermediate apertured portion 58 disposed about the sleeve 55, is resiliently biased towards the space 49 by a spring 59, as best shown in Fig. 3. When the valve member 53 and stem 54 are in the raised position .seen in Fig. 1, the notch 56 receives the sharp straight edge portion 60 at the aperture 58 of the rod 57, the hollow sleeve 55 also being notched to allow the edge portion 60 to engage the notch 56 of the valve stem.

When the valve member 53 is in the raised or open position shown in Fig. 1, the space 50 of housing 46 is at the same pressure as the pressure in the chamber 38 into which air passes through the dust separating member 17. As shown, such communication between space 50 and chamber 38 is efiected by conduits 61 and 62. Accordingly, during normal operation of the cleaner when the valve 53 is open, the pressures in spaces 49 and 50 at opposite sides of the diaphragm 48 are essentially the same as the pressures prevailing at opposite sides of the dust separating member 17. During such normal cleaner operation, dust-laden air is drawn into the inlet 19 of conduit 18. The dust and dirt are trapped at the underside of the dust separating member, and air free of such foreign matter passes into the chamber 38 and thence through the collar 32 and past motor fan unit 33 to be discharged at the outlet 34. When the dust separating member17is clean, the pressure differential at the opposite sides thereof is relatively small. Under these conditions, the pressure in space 50, aided by the biasing action of the spring 59, will be effective to maintain the sharp edge portion 60 of rod 57in engagement with the notch 56 of the valve stem 54, so that the valve 53 will remain in its open position and the space 50 will be in communication with the chamber 38.

However, when the dust separating member 17 becomes clogged, due to dust janddirt trapped at the underside thereof, the pressure in space 50 will be reduced sufliciently to allow the diaphragm,48 to move against the biasing action of the spring 59, thereby causing the rod 57 to be disengaged from the notched portion 56 of the valve stem 54. Under these conditions, the valve stem 54 and valvemember 53, due to force of gravity, move from the position shown in Fig. 1 to the position shown in Fig. 2. When the valve member 53 is in the closed position seen in Fig. 2, the normal flow of air through the conduit 18, dust separating member 17 and chamber 38 is stopped, the suction effect produced by the motor fan unit 33 now being efiective,.through conduits 61 and 62, to withdraw air from space 50 of the housing 46 to create a sub-atmospheric pressure in this space while the space 49 is at atmospheric pressure.

In accord with the invention the vacuum produced by the motor fan unit 33 is effectively employed to initiate operation of diaphragm operated mechanism embodied in the housing 47. As shown, the housing 47, which is formed integrally with the air inlet conduit 18, is divided by ahorizontal partition'63 into top and bottom spaces 64 and 65, respectively; and the conduit 62, which is .connected to the inlet of the motor fan unit 33 at the V a flexible diaphragm-70 which is provided in the bottom space 65. A small opening 71 is formed in the partition 63 so that the spaces64 and 65 will be in restrictedcommunication with one another.. The housing 47 is also provided with an end wall-72 which is removably secured 1n position in any suitable manner (not shown), so that access may be hadinto thespaces 64 and.65, respectively.

During normal operation of the cleaner, the parts thereof are in the positions shown in "Figs. 1, 4 and 5. When the pressure differential across the dust separating member 17 reaches a definite value due to clogging by dust and dirt trapped at the underside thereof, the diaphragm 48 in housing 46 becomes responsive to actuate the rod 57 and allow the valve member53 to'move downwardly by its own weight to the closedposition shown in Fig. 2, as previously explained. The suction efiect produced by the motor fan unit 33 now becomes efiective to produce a vacuum or sub-atmospheric pressure in space 50 of housing 46, as previously explained, and also in the top space 64 of the'housing47. While the evacuation of the space 50 is effected relatively rapidly by the motor fan unit 33, the evacuation of thespace 64 is effected slowly since the latter is in communication with the space 65 through the small opening 71-in the partition 63.

When the space 64 is evacuated sufficiently and the sub-atmospheric pressure therein reaches a definite value, the diaphragm 66 moves downwardly from 'the position shown in-Figs. 1 and 4 to the position shown in Fig. 2

responsive to atmospheric pressure acting on the top.

surface of the diaphragm Under these conditions the stirrup 39 is moved downwardly and the bridge member 25 becomeseffective to compress the springs 43, thereby producing slack in the folds 21 of the dust separating member 17, as shown in Fig. 2 and-described above. When this occurs the valve 68 in the housing47' is still in its closed position, as seen in Fig. 1. However. air continues to be withdrawn from both of the spaces64 and 65 by the suction effect produced by the motor fan unit 33, the air withdrawnfrom the space 65 passing into the space 64 through the restricted or fine opening 71 in the partition 63.

Space 79 is at atmospheric pressure by reason of the opening 200 in the top cover 20, as shown in Figs. 1, 2 andS, and when the pressure in the-bottom space 65 becomessufiiciently reduced, the valve member 68 is moved upwardly from the seat 67 responsive to the atmospheric pressure in space 79 acting against the underside of the diaphragm 70. In other words, atmospheric pressure in the space 7.9 acting against the diaphragm 7t) eventually becomes effective to overcome the weight of the valve 68 and stem :69 and also the counteracting atmospheric pressure tending to maintain the valvemember 68in its closed position. Accordingly, the elfective cross-sectional areas of thediaphragm 70 and the valve member 68 are such that, when the sub-atmospheric or partial vacuum in F the space. 65 reaches a definite value, the total pressure acting on the underside of the diaphragm 70 will be effective to overcome the weight of the 'valve member 68 and stem 69 and also the total counteracting pressure acting downwardly on the top surface of the valvemem ber 68.

With the valve member 68 now in the raised or open position shown in Fig. 2, the space 64 is immediately at atmospheric pressure and hence both sides of the diaphragm 66 are subjected to the same pressure. Accordingly, the diaphragm 66 is no longer effective to hold down the stirrup 39 .and the springs 43 become operable to impart a quick and sudden upward'thrust or movement to the dust separating member 17, thereby snapping -the. folds 21 to dislodge dust and dirt from the underside thereof in the manner explained above.

When the valve member 68 is raised to its open. position, atmospheric air can also pass through the opening 71 inpartition 63 into the bottom space 65 of the housing .47, thereby increasing the pressure in the space65. When the pressure differential at opposing sides of the diaphragm 70 reaches a definite low value, the weight of the valve member 68 and stem 69overcomes the effective upwardly acting pressure on this diaphragm, thereby allowing the valve member 68 to move to its closed position on the seat 67. When this occurs, the space 64.

again will be. evacuated. due to withdrawal-of air therer rcmthrc sh con ui 62hr h mo orfa ni 3. In

, motor. fan unit 33 when the suction line is completely closed or shut off. After the dust separating member 17 has been shaken anl mber of times and the sub-atmospheric pressure in the. space50 has reached a definite low value, upward. movement is imparted to valve member 53 and stem 54.

This .is so, because,.while,the top face or side of the diaphragm S2 and the undersideof :the valvemember 53" are subjected to the same sub-atmospheric pressure, the area of the top face of the diaphragm is considerably larger than that of the underside of the valve member 53 when it is seated on the collar 32. Also, since the region of the diaphragm 52 extending radially outward from the valvemember 53 when the latter is seated on the. collar 32 Willbe subjected to the atmospheric pressure in the space 38, upward movement of the diaphragm 52 is further promoted.

Hence, when upward movement of valve member 53 i and ste1ri54 is effected, the pressure in the space 50 will again be sufliciently high so that the pressure prevailing in this space, aided by the spring 59, will be eifective to hold the valve member 53 in the raised or open position seen .in Fig. 1. Under these conditions normal operation of the cleaner is resumed in which air is drawn into the inlet 19 of conduit 18, and, after passing through the dust separating member ,17, flows through the chamber 33 and motor fan unit 33 and is discharged at the outlet 34. During such normal operation of the cleaner, the ,diaphragm or movable member 66 is unaffected by the full.s uction eifect produced by the motor fan unit 33 during normal circulation of air in its path of flow between the inlet Hand outlet 34. When the dust separating member 17 again becomes clogged withdust and dirt at the underside thereof and the pressure differential at opposite sidesof the diaphragm 48 once more reaches a definite value, the rod 57 is then caused to move again and release the stem 54 of valve'member 53 to allow the latter to move to its closed position and instigate operation of the pneumatic or fluid operated mechanism for mechanically shaking the dust separating member 17 in the manner explained above.

6 In Fig. 6 I have shown a modification of the fluid operated mechanism for shaking the dust separating member 17. In Fig. 6 the housing 47' is formed integrally with the suction inlet conduit 18' into which air is drawn in at the inlet 19'. The housing 47' is similar to.- the housing 47 described above in that a partition 63' having a restricted opening 71 defines the top and bottom spaces 64 and 65', respectively. The diaphragm 66' is provided for the top space 64' and the diaphragm 70' is provided for the bottom space 65', the diaphragm 70' being connected to the stem 69 of the valve member 68' having a seat 67' in the top space 64'.

In the modification of Fig. 6, the housing 47' is provided with a space 73 above the diaphragm 66, the latter being connected to a link 74 whichextends upwardly through an opening inthe top wall 75 of the space 73 and is secured at its ,upper end to the. stirrup 39. The top wall of the chamber ,64' is formed with a 21 of the dust separating member 17 are not always fully stretched in the first-described embodiment of the invention. By providing the modification shown in Fig. 6 and just described, the diaphragm 66' during normal operation of the cleaner is always subjected at both sides thereof to the same pressure. 66' is free of any forces during normal operation of the cleaner tending to interfere with the fully stretched out position of the folds 21 of the dust separating member 17.

In view of the foregoing, it will now be understood that I have provided an improved fluid operated mechanism for automatically shaking the suction cleaner filter element 17, the operation ofthe mechanism being initiated by the pressure differential at opposite sides of the filter clement. After the valve member 53 moves from the position shown in Fig. l to the position illustrated in Fig. 2, the normal circulation of air through the suction cleaner is stopped and the flow of air from the filter element 17 to the suction inlet 32 of the motor fan unit 33 is temporarily shut off.

With the valve member 53 in its closed or seated position, the suction effect developed by the motor fan unit 33 is effectively employed to put the filter element shaking mechanism into operation. This mechanism, which includes the diaphragm operated motor embodied in the housing 47, stirrup 39, bridge member 25 and springs 43, imparts several thrusts or snapping movements in succession to the filter element 17. After the dust and dirt are dislodged from the filter element in this manner, the valve member 53 agains moves to its open position in Fig. l and normal circulation of air through the cleaner again takes place automatically. Hence, during the interval of time the filter element 17 is being shaken, there is no circulation of air in the upper part of the receptacle 14 through the filter element toward the suction inlet of the motor fan unit.

Although I have shown and described several embodiments of my invention, I do not wish to be limited to the particular arrangements set forth, and I intend in the following claims to cover all modifications which do not depart from the spirit and scope of my invention.

What is claimed is:

1. In a suction cleaner having a casing provided with an inlet and an outlet, amotor fan unit for normally circulating air in a path of flow between the inlet and outlet, a movable filter element in the path of flow for removing dustfrom air which passes therethrough, a member movable between first and second positions, means connecting said member and said filter element, said member being unaffected by the full suction effect produced by said motor fan unit during normal circulation of air in its path of flow between the inlet and outlet, means including said filter element when clogged with dust to produce an operating condition which reduces the efficiency of the cleaner, means responsive to said operating condition for subjecting one side of said member to the suction effect produced by said motor fan unit to cause said member to move from its first to its second position and effect movement of said filter element in one direction, and means operable to move said member from its second to its first position and effect movement of said filter element in the opposite direction.

2. In a suction cleaner having a casing provided with an inlet and an outlet, a motor fan unit for normally circulating air in a path of fiow between the inlet and. outlet, a movable filter element in the path of flow for In this way the diaphragm.

*removing'dust from air which passes'therethrough, a

:member movablebetween first and second positions,

means connecting 'said member and said filter element,

. means for biasing said member to its first position, said 'mem ber being unaffected by the full suction effect produced by said motor fan unit during normal circulation of air in its path of flow between the inlet and outlet, means including said filter element when clogged with dust "to produce an operating condition which reduces the efficiency of the cleaner, means responsive to said operating condition for subj'ectingone side of said member to the suctioneffect produced by said motor fan unit to cause said member to'move from its first to its second position against the action of said biasing means and effect movement of said filter element in one'direction, and means operable to move said member from its second to its first position with the aid of said biasing means and effect movement of said filter element in the opposite direction.

3. In a suction cleaner having a casing provided with an inlet and an outlet, a motor fan unit for normally circulating air in a path of flow between the inlet and outlet, a movable filter element in the path of flow for removing dust from air which passes therethrough, a member movable between first and second positions, means connecting said member and said filter element, means for biasing said member to its first position, said member being unaflfected by the full suction effect produced by said motor fan unit during normal circulation of air in its path of flow between the inlet and outlet, means including said filter element when clogged with dust to produce an operating condition which reduces the efficiency of the cleaner, means responsive to said operating condition for subjecting one side of said member to the suction effect produced by said motor fan unit to cause said member to move from its first to its second position at a first rate of speed against the action of said biasing means and effect movement of said filter element in one direction, and means operable to move said member from its second to its first position at a second higher rate of speed with the aid of said biasing means and effect movement of said filter element in the opposite direction at a faster rate than when movement thereof is effected in the one direction.

4. In a suction cleaner having a casing provided with an inlet and an outlet, a motor fan unit for normally circulating air in a path of flow between the inlet and outlet, a movable filter element in the path of flow for removing dust from air which passes therethrough, the region into which air passes through said filter element being subjected to the suction effect produced by said motor fan unit, a member movable between first and second positions, means connecting said member and said filter element, said member being unaffected by the full suction effect produced by said motor fan unit during normal circulation of air in its path of flow between the inlet and outlet, means including said filter element when clogged with dust to produce an operating condition which reduces the efficiency of the cleaner, means responsive to said operating condition to reduce the extent to which said region at one side of said filter element is subjected to the suction effect produced by said motor fan unit and increase the extent to which one side of said member is subjected to such suction effect to cause said member to move from its first to its second position and effect movement of said filter element in one direction, and means operable to move said member from its second to its first position and effect movement of said filter element in the opposite direction.

5. In a suction cleaner having a casing provided with an inlet and an outlet, a motor fan unit for normally circulating air in a path of flow between the inlet and outlet, a movable filter element in the path of flow for removing dust from air which passes therethrough, a

-member movable between first and second positions,

means connecting said member and said filter element, means for biasingsaid member to'the first position, said member being unaffected by the full suction effect produced by said motor fan unit during normal circulation of .air in its path of flow between the inlet and outlet,

means including said filter element when clogged with dust to produce an operating condition which reduces the efficiency of the cleaner, first means responsive to said operating condition for subjecting one side of said member to the suction effect produced by said motor fan unit to cause said member to move from its first to its second position against the action of'said biasing means and effect movement of said filter element in one direction, and additional means responsive to said operating condition to reduce the extent to which the one side of said member is subjected to the suction effect produced by said motor fan unit and render said biasing means operable to move said member from its second to its first position and effect movement of said filter element in the opposite direction.

6. Apparatus as set forth in claim in which slack is produced in said filter element when movement thereof is effected in the one direction with movement of said member from its first to its second position, said biasing means being resilient in character and capable of imparting a quick and sudden movement to said filter element to snap the latter and dislodge dust therefrom when it is rendered operable to move said member from its second to its first position and effect movement of said filter element in the opposite direction to the one direction.

7. In a suction cleaner having a casing provided with an inlet and an outlet, a motor fan unit for circulating air in a path of flow between the inletand outlet, a movable filter element in the path of flow for removing dust from air which passes therethrough, a first region of said path of flow into which air passes through said filter element being subjected to the suction effect produced by said motor fan unit during normal operation of the cleaner, structure providing a second region which includes a member defining a wall part thereof, said member being movable between first and second positions, means connecting said member and said filter element,

means including said filter element when clogged with dust to produce an operating condition which reduces the efficiency of the cleaner, first means responsive to said operating condition for transferring the suction effect produced by said motor fan unit from said first region to said second region to cause said member to move from its first to its second position and effect movement of said filter element in one direction, and second means for intermittently reducing the extent to which said second region is influenced by the suction effect produced by said motor fan unit to cause said member to move from its second to its first position and effect movement of said filter element in the opposite direction, said member, when said last-mentioned means becomes ineffective to reduce the extent to which said second region is influenced by the suction effect produced by said motor fan unit, again becoming operable responsive to the suction effect produced in such second region to move from its first position to its second position and effect movement of said filter element in the one direction.

8. Apparatus as set forth in claim 7 in which said first means, which is responsive to said operating condition, includes structure for rendering said second region subject to the influence of the suction effect produced by said motor fan unit even when the influence of such suction effect at said second region is reduced by said second means.

9. Apparatus as set forth in claim 8 which includes means for biasing said member to its first position, said member moving from its first position to its second position responsive to the suction effect produced at said second region by said motor fan unit against the action of said biasing means, said member moving from its second to its first positionywith the aid of said biasing means when said second means reduces the extent to which said second region is influenced by the suction effect produced by said motor fan unit.

10. Apparatus aslset forth in claim 7 in which said second means becomes operable 'to reduce the extent to which said second region is influenced by the suction effect of said motor ,fan unitafter said member has moved from its first to its secondposition.

11. Apparatus as set forth in claim 7 in which said second means becomes operable responsive to the suction effect produced by said motor fan unit.

12. In a suction cleaner having a casing providedwith an inlet and an outlet, a motor fan unit for circulating air in a path of flow between the inlet and outlet, a movable filter element in the path of flow for removing dust from air which passes therethrough, a first region of said path of flow into which air passes through said filter element being subjected to the suction effect produced by said motor fan unit during normal operation of the cleaner, structure providing a second region which includes a member defining a wall section thereof, conduit means connecting said second region and the suction inlet of said motor fan unit, said member being movable between first and second positions, means connecting said member and said filter element, means including said filter element when clogged with dust to produce an operating condition which reduces the efficiency of the cleaner, first means responsive to said operating condition for transferring the suction effect produced by said motor fan unit from said first region to said conduit means and second region communicating therewith, said member,

when the suction effect produced by said motor fan unit is transferred to said second region, being movable from its first to its second position and effecting movement of said filter element in one direction, and second means for intermittently establishing communication between said second region and the atmosphere to cause said member to move from its second to its first position and effect movement of said filter element in the opposite direction, said member, when said second means becomes ineffective to establish communication between said second region and the atmosphere, again becoming operable responsive to the suction effect produced in such second region to move from its first position to its second position and effect movement of said filter element in the one direction.

13. Apparatus as set forth in claim 12 in which said second means comprises structure providing a third region in restricted communication with said second region, such third region including a second movable member forming a wall section thereof, said second region having an opening in a wall section thereof, valve means for closing such opening, and means for controlling said valve means responsive to said second movable member.

14. Apparatus as set forth in claim 12 in which said first means comprises a part movable responsive to said operating condition, a valve member which-is movable responsive to movement of said part and disposed at a place in the path of flow between said first region and the suction inlet of said motor fan unit for controlling flow of air, said conduit means communicating with the suction inlet of said motor fan unit when said valve member is in its closed position.

15. Apparatus as set forth in claim 14 in which said 11 l2 tor fan unit when said valve member is in'its closed References Cited in the file of this patent position.

17. Apparatus as set forth in claim 16 in which said UNITED STATES PATENTS structure forming said first means provides said first space ,3 ,3 8 Leathers June 1, 1943 and also a second space and a partition therebetween, a 5 ,567 Lofgren et al Apr. 1 ,l952 movable portion forming a section of said partition, said ,63 ,20 Bruckner Mar. 31, 1953 second space being in communication with.the path of 2,645,303 Meyerhoefer July 14, 19 53 flow at a region between the inlet and said filter element, and means responsive to movement of said portion of said FOREIGN PATENTS partition and said part for controlling said valve member. 10 63,286 France Sept. 22, 1941 

